Protector for electric circuits

ABSTRACT

A female connector is connected to a conductor and normally telescopes over a male connector on one end of a fuseholder, but is will respond to a separating force, smaller than the elastic limit of that fuseholder, to release that male connector; and a sleeve of insulating material normally encases and insulates the connection between that male connector and that female connector.

United States Patent 1191 111 3,753,192 Urani Aug. 14, 1973 [54]PROTECTOR FOR ELECTRIC CIRCUITS 3,356,806 12/196; Urani 3,417,359 12 196Urani... l [75] Invent: i 3,518,600 6/1970 Urani 337/192 x [73]Assignee: McGraw-Edlson Company, Elgin, 111.

[22] Filed: No 22 1971 Primary Examiner-Bernard A. Gilheany AssistantExaminer-F. E. Bell [211 App]. No.: 200,711 AtmMey Rey Eilers RelatedU.S. Application Data I [60] Continuation of Ser. No. 871,233, Nov. 3,1969,

which is a division Of Sci. NO. 796,520, Feb. 4, 1969, 7 ABSTRACT Afemale connector is connected to a conductor and normally telescopesover a male connector on one end (gl. 337l2llllll3h3gls of a fuseholder,but is will respond to a separating 58] Fieid "5 201, force, smallerthan the elastic limit of that fuseholder, 21 1 to release that maleconnector; and a sleeve of insulating material normally encases andinsulates the connection between that male connector and that femalecon- [5 6] References Cited necton UNITED STATES PATENTS 3,085,1384/1963 Brown et a1. 337/192 4 Claims, 7 Drawing Figures PROTECTOR FORELECTRIC CIRCUITS This is a continuation of application Ser. No. 871,233filed Nov. 3, 1969, which was a division of application Ser. No. 796,520filed Feb. 4, 1969 now US. Pat. No. 3,518,600.

This invention relates to improvements in Protectors For ElectricCircuits. More particularly, this invention relates to improvements infuseholders and in separable connectors used therewith.

It is, therefore, an object of the present invention to provide animproved fuseholder and. an improved separable connector used therewith.

It is desirable to interpose fuseholders between the sockets for streetlamps and the power lines connected to. those sockets; because the fuseswithin those fuseholders can provide important electrical protection.That electrical protection can be impaired and those fuseholderscan bedamaged, when vehicles strike and break off those street lamps; becausethe conductors within those street lamps can, as those street lamps arebroken off, applydestructive' tensile forces to the fuseholders andtothe connectionsbetween those fuseholders and the powerlines- It would bedesirable toequip a fuseholder, to be. interposed between the socket of'a street lamp. and the. power; line. connected to that socket, with aseparable connector which would respond to forces smaller than theelastic limit of that fuseholder toseparate}. from: that fuseholder; andit wouldbe desirabletoprovide that separableconnector with insulationwhich: would? remain with that separable connector as;itisseparatedifrom thatfuse-hold'er. Such a separable connector and the.insulation therefor would keepz that fuseholder from being subjected'todc-- present. invention; to equip. a fuseholder, to be interposedbetweenthe socket of a street lamp and the powerline connected to: that socket,withia separable connector whichwill respond to forcessmaller thantheelastic limit of that. fuseholder. to separate from that" fuseholder,andto provide: that separable connector with insulation: which: will.remainwith that. separable connector as it is separated from thatfuseholder.

Other andfurther objects and advantages of the present invention shouldbecome? apparent from anexamination of the drawing'and accompanying:description.

In t the drawingandaccompanying description several preferredembodiments ofthe present invention are shown and described-butsit istobeunderstood that 'the drawing and accompanying description are for thepur pose of illustration only andd'o not'limit the invention and thatthe invention wilhbe' defined by-the' appended claims.

- In the drawing;

FIG; 1 is a partially sectioned. view-ofv afuseholder, ofa'separable.connector used'with that fuseholder; of. a sleeve'ofrinsulatingmaterialused with that separable connector, and of two'boots of insulatingmaterial used with thatfuseholder and with'th'at'separable connector,

FIG. 2isa cross-sectional view that is-taken along the plane-indicatedby; the line. 2 -2"- in' FIG 1,

1 FIG. 3" is. a. partially: broken-away, side elevational view of oneofthe-boots-ofinsulatingmaterial shown in'FIG. 1,

FIG; 4 isa-partially sectionedside view showingthe fuseholder of F165 1assembledwith a different separa;

- ble connector,

FIG. 5 is a partially sectioned view of the different boot shown in FIG.4,

FIG. 6 is a sectional view through the different boot shown in FIG. 4,and it'is taken along the plane indicated by the line 6-6 in FIG. 5, and

FIG. 7 is a partially sectioned view of a different fuseholder and of aboot of insulating material therefor.

Referring to the drawing in detail, the numeral 20 generally denotes afuseholder of the type shown in my US. Pat. No. 3,356,806 for ProtectorsFor Electric Circuit which was granted Dec. 5, i967; and that fuseholderhas a body portion 21 and a body portion 23. The body portion 23 has anexternal thread 25 at the left-hand end thereof, has a hexagonalwrenchreceiving surface 27 adjacent that thread, and has a maleconnector 22 projecting outwardly beyond the right-hand end thereof. Themale connector 22 has an enlarged diameter portion 24 that abuts thebody portion 23. The body portion 21 has a nut 26 with an internalthread rotatably mounted on the right-hand end thereof and has aterminal 76, with an elongated recess in the shank thereof, projectingoutwardly beyond the left-hand end thereof. The body portions 21 and 23are hollow; and they coact to form a recess which will accomodate acartrid'getype electric fuse, all in the manner shown by my said patent.

The numeral 28 generally denotes a separable connector of tubularconfiguration; and that separable connector has a continuous andunbroken sleeve-like portion30 at the right-hand'thereof, and'h'aselongated, flexible." fingers 34 ,36, 38and 40 at the left-hand endthereofwhich define an elongated recess 32, The fingers 34', 36,38'and40 have radially'extending flanges" at'thefree-ends thereofi andthe inner surfaces of those fingers can be spread'far'enough-apart toaccommodate the: male connector 22 on'the body portion" 23 of thefusehold'er20. As a result, the fingers 34, 36, 38 and 40 enable theseparable'connector 28 to act as a female connector. However,- a splitring 42 of resilient mate'- rial, such as spring steel, encircles thefree ends of the fingers 34, 36,. 38 and 40; and that split ring biasesthose free ends-into a position wherein they define anopeningwithadiameter smaller than the diameterof the" male connector 22on the body portion 23. This means that the male connector 22 mustdistend that split ring as it is moved into the elongatedrecess 32defined by the fingers 34', 36,-38 and 40. After that-male connectorhasbeen moved into the elongated recess 32, the force which the splitring 42 applies to the fingers 34, 36,38'and 40will hold those fingersin intimate engagement with the male connector 22, thereby providinggood mechanical securement and-good electricalcontact betweenthosefingers andthat male connector.

The numeral 44 denotes a-sleeve of insulating material,isuch asneopreneyand the inner diameter of the right-hand'end 'of that'sleeve isslightly smaller than the diameter of the separable connector 28. As aresult, thatright-hand endof that sleeve hasapress fit-with thatseparable connector. An annular recess 46 is provided in thesleeve 44;andthat recess is dimensioned to accommodate the split ring 42. Afurther annular recess 481s provided in the sleeve 44; and that recessis dimensioned to accommodate the radially directed flanges at the freeends of the fingers 34', 36, 38 and 40 of the separable connector 28. Alarger diameter recess 50 is provided in the left-hand of the sleeve 44;and the inner diameter of that sleeve is slightly smaller than thediameter of the body portion 23 of the fuseholder 20. As a result, therecess 50 will provide a close fit with that body portion when theleft-hand end of the sleeve 44 is telescoped over that body portion. Ashoulder 52 is provided in the sleeve 44 between the annular recess 48and the larger diameter recess 50; and that shoulder will help preventaccidental separation of that sleeve from the separable connector 28.

The numeral 54 denotes an insulated conductor which has the right-handend thereof freed of insulation; and that right-hand end is telescopedwithin the elongated recess in the shank of the terminal 76 of the bodyportion 21 of the fuseholder 20. Once that end of that conductor hasbeen telescoped within that recess, the terminal 76 will be crimped,staked, or otherwise deformed to provide a permanent electrical andmechanical connection between that terminal and that end of thatconductor. The numeral 56 denotes an insulated conductor which has theleft-hand end thereof freed of insulation; and that left-hand end istelescoped within the continuous and unbroken sleeve-like portion 30 atthe right-hand end of the separable connector 28.

. Once that end of that conductor has been telescoped within thatportion, that portion will be crimped, staked or otherwise deformed toprovide a permanent electrical and mechanical connection between'thatconductor and the separable connector 28.

While the separable connector 28 will be permanently connected to theconductor 56 by the crimping, staking, or other deforming of thesleeve-like portion 30, that separable connector will have only africtional engagement with the male connector 22 of the body portion 23of the fuseholder 20. That frictional engagement will provide holdingforces which are strong enough to prevent accidental separation of theseparable connector 28 from the male connector 22, and which are strongenough to provide a low resistance electrical connection between thatseparable connector and that male connector; but those forces will besmaller than the elastic limit of the fuseholder 20. This is important;because it enables the separable connector 28 to release the maleconnector 22 before the fuseholder 20 can be subjected to potentiallyhurtful forces. Also, the separable nature of the connectors 22 and 28is important in rendering a broken-off street lamp electrically dead sopersons coming incontact with that street lamp will not receive anelectrical shock.

The numeral 58 generally denotes a boot of insulat: ing material, suchas neoprene; and that boot has a frusto-conical left-hand end 60 and acylindrical right-hand end 62. Annular ribs 64 are provided at theexterior of the frusto-conical end 60, and annular ribs 66 are providedat the interior of the cylindrical end 62. The unstressed diameters ofthe annular ribs 66 at the interior of the cylindrical end 62 areslightly smaller than the diameter of the body portion 21, and hencethose annular ribs will provide a close fit with that body portion onthat conductor, as that left-hand end is distended to permit thatconductor to be passed through it.

FIG. 3 shows the configuration of the boot 58 a s that boot is sold; andit will be noted that the boot 58 in FIG. 1 has bad part of theleft-hand end 60 thereof cut off. That part was cut off because theinsulation on the conductor 54 has a diameter which is appreciablylarger than the inner diameter of the smallest diameter portion of theleft-hand end 60 of the boot 58, as that boot is sold. Specifically, itwill be noted that there are eight ribs 64 at the exterior of theleft-hand end 60 of the boot 58 shown in FIG. 3, but there are onlyseven ribs 64 at the exterior of the boot 58 shown in FIG. 1 theleft-handmost rib 64 and the portion of the left-hand end 60 betweenthat first rib and the second rib having been cut off.

In determining where the frusto-conical left-hand end 60 of the boot 58should be cut, one end of the insulated conductor 54 will be telescopedthrough the cylindrical end 62 of the boot 58 and moved into engagementwith the inner surface of the frusto-conical lefthand end 60. When alight pressure on the conductor 54 is unable to cause the left-hand endof that conductor to move any further through the frusto-conicallefthand end 60 of the boot 58, the portion of that frustoconicalleft-hand end into which the insulated conductor 54 did not extend willbe cut off, by appropriate use of a knife, scissors or the like. The cutwill be made to the left of the right-handmost annular rib 64 throughwhich the end of the insulated conductor 54 did not extend; and hencethat rib and the part of the frustoconical left-hand end 60 which isadjacent to, and slightly to the right of, that rib will have to bedistended as the conductor 54 is subsequently pressed through thatfrusto-conical left-hand end. After the frustoconical left-hand end 60of the boot 58 has been cut, the insulated conductor 54 will beintroduced into that boot by first passing it through the frusto-conicallefthand end 60 and then moving it through the cylindrical end 62. Atsuch time, the bared end of that conductor will be telescoped into theterminal 76 of the body portion 21 of the fuseholder 20 and then thatterminal will be crimped, staked or otherwise deformed to provide apermanent electrical and mechanical connection between that conductorand that terminal. Thereafter, the boot 58 will be shifted to the right,relative to the conductor 54, until the cylindrical end 62 telescopesonto the body portion 21 of the fuseholder 20.

The engagement between the frusto-conical end 60 of the boot 58 and theinsulation on the conductor 54 will be snug and will be water-resistant.Similarly, the engagement between the annular ribs 66 at the innersurface of the cylindrical end 62 of that boot and the body portion 21of the fuseholder 20 will be snug. Those annular ribs will coact withthat body portion to provide a plurality of spaced seals; and thoseseals will effectively resist the entry of water into the joint betweenthe boot 58 and the fuseholder 20. I

The numeral 68 generally denotes a boot which can be identical to theboot 58.'The annular ribs 69 within the cylindrical, left-hand end 70 ofthe boot 68 will be distended to telescope over the right-hand end ofthe sleeve 44; and those ribs will coact with that sleeve to provide aplurality of spaced seals. The frusto-conical right-hand end 72 of theboot 68 will be cut to provide a snug and intimate engagement with theinsulation on the conductor 56; and, as with the boot 58, there are justseven annular ribs 74 at the exterior of the righthand end 72 of theboot 68. The boot 68 will coact with the sleeve 44 on the separableconnector 28 and with the insulation on the conductor 56 to providewaterresistant joints on opposite sides of the electrical connectionbetween that conductor and that separable connector.

The fuseholder 20 has a water-tight seal between the body portion 21 andthe terminal 76 thereof, has a water-tight seal between the body portion23 and the male connector 22 thereof, and will provide a water-resistantseal between the body portions 21 and 23 thereof. The boot 58 will coactwith the body portion 21 and with the insulation on the conductor 54 tokeep water away from the electrical connection between that conductorand the terminal 76; and the sleeve 44 of insulating material and theboot 68 will coact with the body portion 23 and with the insulation onthe conductor 56 to keep water away from the electrical connectionbetween that conductor and the separable connector 28 and away from theelectrical connection between that separable connector and the maleconnector 22. As a result, the fuse within the fuseholder 20 and theconnections between that fuseholder and the conductors 54 and 56 areprotected against moisture and water.

The conductor 56 will be connected to the line side of the circuit, andthe conductor 54 will be connected to the load side of the circuit. Themale connector 22 will thus be the load connector and the femaleconnector 28 will thus be the line connector of 30 the connectionprovided by those two connectors; and this is important, because thatmale connector will be exposed whereas that female connector will beprotected whenever that connection is interrupted. Specifically, theportion'of the sleeve 44 of insulating material which defines the recess50 will project outwardly beyond the left-hand end of the femaleconnector 28, and will thus keep that female connector from contactingany nearby objects or the ground as that female connector and the maleconnector 22 are separated. Further, that portion of the sleeve 44 ofinsulating material will keep a repairman from being shocked as he picksup the line connector of the connection provided by the male connector22 and the female connector 28.

It should also be noted that the boot 68 will remain in engagement withthe conductor 56 and with the sleeve 44' of insulating material wheneverthe connection provided by the male connector 22 and the femaleconnector 28 is interrupted. Specifically, the annular ribs 69 at theinterior of the cylindrical portion 70 of that boot will continue toremain in engagement with the exterior of the right-hand portion of thesleeve 44 of insulating material, and the small diameterrighthand end 72of that boot will remain in engagement with the insulation on theconductor 56. As a result, that boot will continue to encase and toinsulate the connection between the conductor 56 and the femaleconnector 28 whenever the connection between that female connector andthe male connector 22 is interrupted. The overall result is that thefemale connector 28 will continue to be protected and shielded and theconnection between that female connector and the conductor 56 willcontinue to be encased and shielded whenever the connection provided bythe male connecto'r 2 2 and the female connector 28 is interrupted.

To restore the connection provided by the male connector 22 and thefemale connector 28 the repairman will grip the cylindrical end 62 ofthe boot 58, will grip the cylindrical portion of the boot 68,- and willguide the tapered tip of the male connector 22 into the re maleconnector 28. Thereafter, that repairman will apply relatively strongtelescoping forces to the body portion 21 of the fuseholder 20 and tothe female connector 28 to effect full telescoping of the male connector22 into that female connector. Because the split ring 42 will cause theends of the fingers 34, 36, 38 and 40 to strongly resist the telescopingof the male connector 22 into the female connector 28, the repairman maywant to press against the left-hand end of the body portion 21 of thefuseholder 20 and to grip the sleeve-like portion 30 of the femaleconnector 28; and the walls of the boots 58 and 68 will be made thinenough to enable that repairman to do so. Consequently, although theconnection provided by the male connector 22 and the female connector 28is a blind connection, the boots 58 and 68 will enable the repairman tomake that connection and to sense that the connection has been made.

Where the walls of the boots 58 and 68 are made quite thin, thefrusto-conical ends of those boots can tend to tear as thosefrus'to-conical ends are telescoped over, and are then slid along, theinsulation on the conductors 54 and 56. The walls of the boots 58 and 68can be made quite thin, and yet the frusto-conical ends of those bootscan be made very resistant to tearing, by providing the annular ribs 64and 74, respectively, at the exteriors of the frusto-conical ends 60 and72 of the boots 58 and 68.

Referring to FIG. 4, the numeral 82 denotes a conductor which can beidentical to the conductor 54, and which will be electrically andmechanically connected to the terminal, not shown, on the left-hand bodyportion of the fuseholder 20. The junction between that conductor andthat terminal will be encased and insulated by a boot 58 which can beidentical to the boot 58 shown in FIGS. 1 and 3. The numeral 84 denotesa female connector with a rod-like projection 86 at the righthand endthereof and with four circumferentially spaced fingers adjacent theleft-hand thereof. Because FIG. 4 is a side view, only two of thosefingers, namely the fingers 88 and 90, are shown. The female connector84 of FIG. 4 will closely resemble the separable connector 28 in FIGS. 1and 2, except for the fact that the female connector 84 has a rod-likeprojection 86 at the right-hand end thereof whereas the separableconnector 28 has a sleeve-like portion 30 at the right-hand end thereof.

A split ring 92 encircles the free ends of the fingers 88 and 90 plusthe other two fingers of the female connector 84, in the same manner inwhich the split ring 42 encircles the free ends of the fingers 34, 36,38 and I 40 of the female connector 28. The split ring 92 will normallyhold the free ends of the fingers 88 and 90 and of the other two fingersofthe female connector 84 closer together than the diameter of the maleconnector 22 on the body portion 23 of the fuseholder 20; but that splitring will yield to permit that male connector to be telescoped intoposition between the free ends of those fingers. The numeral 93 denotesa sleeve of insulating material which can be identical to the sleeve 44of insulating material in FIGS. 1 and 2; and that sleeve of insulatingmaterial will enclose and insulate the fingers 88 and 90 and the othertwo fingers of the female connector 84, will enclose and insulate thesplit ring 92,

and will enclose and insulate the body portion 23 of the fuseholder 20.

The numeral 94 denotes a connector which has a tubular projection 96extending outwardly from the lefthand end thereof, which has acylindrical socket 98in the right-hand end thereof, which has acylindrical socket 100 in the right-hand end thereof, which has a setscrew 102 communicating with the cylindrical socket 100, and which has asecond set screw, not shown, communicating with the cylindrical socket98. The tubular projection 96 is dimensioned to telescope freely overthe rod-like projection 86 on the female connector 84; but that tubularprojection will be crimped, staked or otherwise deformed into permanentengagement with that rod-like projection. Consequently, the connector 94will, effectively, serve as part of the female connector 84. The socket98 is dimensioned to accommodate the bared end of an insulated conductor104, and the socket 100 is dimensioned to accommodate the bared end ofan insulated conductor 106. The set screw 102 will be tightened toprovide a good electrical and mechanical connection between theconnector 94 and the conductor 106; and the second set screw, not shown,will be tightened to provide a good electrical and mechanical connectionbetween the conductor 104 and the connector 94. The connector 94 and thefemale connector 84 are used where it is desirable to interconnect twoconductors to the male connector 22 of the fuseholder 20.

The numeral 108 denotes a boot which has a cylindrical left-hand endwith internal annular ribs 110, which has a cylindrical central portionwith external annular ribs 112, and which has two frusto-conicalsections 114 and 116 at the right-hand end thereof. The diameters of theribs 1 10 are slightly smaller than the outer diameter of the right-handportion of the sleeve 93 of insulating material which encases thefingers 88 and 90 plus the other two fingers of the female connector 84;and hence those ribs will be distended as they are telescoped over thatportion of that sleeve. Thereafter, the restorative forces within thoseribs and within the cylindrical left-hand end of the boot 108 will causethose ribs to provide a plurality of water-resistant seals with thatportion of the sleeve 93 of insulating material.

The frusto-conical section 114 of the boot 108 will accommodate theconductor 104, which has the lefthand end there-of held within thesocket 98 of the connector 94; and the frusto-conical section 116 ofthat boot will accommodate the conductor 106, which has the left-handend thereof held within the socket 100 of that connector. The unstressedinner diameter of the outer end of each of the frusto-conical sections114 and 116 will be smaller than the diameter of the insulation of theconductors 104 and 106; and hence those outer ends will be distended asthe conductors 104 and 106 are telescoped through those sections.Thereafter, the restorative forces within those outer ends will providewater-resistant seals between the boot 108 and the insulation on thoseconductors.

The sleeve 93 of insulating material will encase and insulate theconnection between the male connector 22 and the female connector 84;and the boot 108 will encase and insulate the connection between thatfemale connector and the connector 94, and also will encase and insulatethe connection between the connector 94 and the conductors 104 and 106.In the event a force is applied to the conductor 82 or to either of theconductors 104 and 106 which causes the female connector 84 to move awayfrom the male connector 22 on the body portion 23 of the fuseholder 20,the sleeve 93 will remain in engagement with that female connector, andthe boot 108 will remain in engagement with that sleeve and with thoseconductors. As a result, the female connector 84, the connector 94, theconnection between them, and the connection between the connector 94 andthe conductors 104 and 106 will continue to be encased and insulatedafter the female connector 84 has been separated from the male connector22 on the body portion 23 of the fuse-holder 20.

As shown by FIG. 7, the boot 108 can be assembled with the body portionof a fuseholder which has a tubular terminal that is large enough toaccommodate the ends of two conductors. Specifically, the boot 108 canhave the internal annular ribs 110 at the cylindrical left-hand endthereof distended to telescope over the right-hand body portion of afuseholder which has a tubular terminal 122 that is large enough toaccommodate the bared ends of two conductors 124 and 126. Thefrusto-conical sections 114 and 116 at the righthand end of the boot 108will snugly accommodate the insulation on the conductors 124 and 126;and the bared ends of those conductors will be held by the crimped,staked or otherwise deformed tubular terminal 122.

The annular ribs 122 on the boot 108 strengthen the cylindrical centralportion of that boot; but they permit that cylindrical central portionto be flexible. If desired, external annular ribs, similar to theannular ribs 64 and 72 of FIG. 1 can be formed on the frusto-conicalsections 114 and 116 at the right-hand end of the boot 108.

While the fuseholders, separable connectors, insulating sleeves, andinsulating boots of the present invention are very useful in streetlighting circuits, they are useful elsewhere too. In fact, thosefuseholders, separable connectors, insulating sleeves, and insulatingboots are usable anywhere external forces can accidentally separate afuseholder from the line or load side of a circuit.

The boots 58, 68 and 108 and the sleeves 44 and 93 will be made frommaterial that is resilient as well as non-conductive as a result, thoseboots and those sleeves will be able to withstand blows and stresseswhen the street lamp or other power consuming device with which they areused is struck which rigid and brittle elements could not withstand. Theoverall result is that the fuseholders, separable connectors, insulatingsleeves and insulating boots of the present invention I can minimize andlargely eliminate the risk of electrical shocks when street lamps andother power consuming devices are struck.

Whereas the drawing and accompanying description have shown anddescribed several preferred embodiments of the present invention itshould be apparent to those skilled in the art that various changes maybe made in the form of the invention without affecting the scopethereof.

What I claim is:

l. A combination which comprises:

an enclosed fuseholder which has a male body portion, a female bodyportion, and means to releasably interconnect said body portions,

said male body portion being hollow but having the outer end thereofclosed, I

saidfemale body portion being hollow but having the outer end-thereofclosed,

said male body portion and said female body portion and said-meanscoacting to releasably enclose and confine acartridge type electricfuse,

a metallic connector carried by and projecting outwardly from one end ofone of said body portions,

a metallic terminal carried by and communicating with the exterior ofthe other of said body portions,

a-water-tight seal between said one body portion and said metallicconnector,

a second'wat'entight seal between said other body portionand saidmetallic terminal, 1

saidmeans releasably holding the inner ends of said body portions-inintimate engagement with each otherto provide a-water-resistant sealbetween said body portions,

whereby said cartridge type electric fuse is normally held within'awater-resistant but readily openable enclosed fuse holder,

a metallic separable connector which is located exteriorly of saidenclosed fuseholder and which normally has one end thereof in telescopedengagement withaportion of the first said metallic connectorand whichhas the other end thereof connectable to aconductor, and

a body of insulating material which is mounted on and directly engages aportion of said metallic separable connector and which moves with saidmetal lic separable connector whenever said metallic separable connectoris separated from the first said met'allicconne'ctor,

the first said metallic connector and said metallic separable connectorbeing dimensioned to provide a frictional securement therebetween whichis strong enough to normally maintain a low resistance: electricalconnection between said fuseholder and said metallic separableconnector,

the first said metallic connector and said metallic separable connectorbeing dimensioned so said frictional securement will automatically yieldto permit the first said metallic connector and said metallic separableconnector to separate from each other in response to a separating forcewhich is smaller than the elastic limit of said fuseholder,

said metallic separable connector and said portion of said firstmetallic connector, which is in telescoped engagement with said metallicseparable connector, being located wholly externally of said one bodyportion of said enclosed fuseholder,

whereby said metallic separable connector can be pulled away from saidfirst metallic connector while said means holds said male body portionand said female body portion in assembled relation and whilethestressapplied to said enclosed fuseholder is well below the elasticlimit of said enclosed fuseholder,

whereby said enclosed fuseholder is protected against damage fromtensile forces which are applied to it by conductors of the circuit thatis protected by the cartridge typevelectric fuse within said enclosedfuseholder.

2. A combination as claimed in claim 1 wherein the first said metallicconnector is a male connector and whereinsaid metallic separableconnector is a female connector, and wherein said metallic separableconnector is a sleeve that is slit at one end thereof to define fingerswhich can telescope over and tightly grip said first said metallicconnector, said metallic separable connector having the other endthereof dimensioned to telescope over the hated end of said conductor.

3. A combination which comprises: an enclosed fuseholder which has amale body portion, a female body portion, and means to releasablyinterconnect said body portions, said male body portion being hollow buthaving the outer end thereof closed, said female body being hollow buthaving the outer end thereof closed, said male body portion'and saidfemale body portion and said means coacting to releasably enclose andconfine a cartridge type electric fuse, metallic connector carried byand projecting outwardly from one end of one of said body portions, ametallic separable connector which is located exteriorly of saidenclosed fuseholder and which normally has one end thereof in telescopedengagement with a portion of the first said metallic connector and whichhas the other end thereof connectable to a conductor, body of insulatingmaterial which is mounted on and directly engages a portion of saidmetallic separable connector and which moves with said metallicseparable connector whenever said metallic separable connector isseparated from the first said metallic connector, the first saidmetallic connector and said metallic separable connector beingdimensioned to provide a frictional securement therebetween which isstrong enough to normally maintain a low resistance electricalconnection between said fuseholder and said metallic separableconnector, the first said metallic connector and said metallic separableconnector being dimensioned so said frictional securement willautomatically yield to permit the first said metallic connector and saidmetallic separable connector to separate from each other in response toa separating force whichqis smaller'than the elastic limit ofsaid'fuseholder, said metallic separable connector and said portion ofsaid first metallic connector, which is in telescoped engagement withsaid metallic separable connector, being located wholly externally ofsaid one body portion of said enclosed fuseholder, whereby saidfuseholder is protected against damage from tensile forces which areapplied to it by conductors of the circuit that is protected by the fusewithin said fuseholder, said metallic separable connector being a sleevewith a plurality of fingers at said one end thereof. 4. A combinationwhich comprises: an enclosedfuseholder which has a male body portion, afemale body portion, and means to releasably interconnect said bodyportions, said male body portion being hollow but having the outer endthereof closed, said female body portion being hollow but having theouter end thereof closed, said male body portion and said female bodyportion and said means coacting to releasably enclose and confine acartridge type electric fuse, a metallic connector carried by andprojecting outwardly from one end of one of said bodyportions, ametallic separable connector which is located exteriorly of saidenclosed fuseholder and which normally has one end thereof in telescopedengagement with a portion of the first said metallic connector and whichhas the other end thereof connectable to a conductor,

a body of insulating material which is mounted on and directly engages aportion of said metallic separable connector and which moves with saidmetallic separable connector whenever said metallic separable connectoris separated from the first said metallic connector,

the first said metallic connector and said metallic separable connectorbeing dimensioned to provide a frictional securement therebetween whichis strong enough to normally maintain a low resistance electricalconnection between said fuseholder and said metallic separableconnector,

the first said metallic connector and said metallic separable connectorbeing dimensioned so said frictional securement will automatically yieldto permit the first said metallic connector and said metallic separableconnector to separate from each other in response to a separating forcewhich is smaller than the elastic limit of said fuseholder, saidmetallic separable connector and said portion of said first metallicconnector, which is in telescoped engagement with said metallicseparable connector, being located wholly externally of said one bodyportion of said enclosed fuseholder, whereby said fuseholder isprotected against damage from tensile forces which are applied to it byconductors of the circuit that is protected by the fuse within saidfuseholder, said metallic separable connector being a sleeve with aplurality of fingers at said one end thereof, and a split ringencircling said one end of said metallic separable connector to enablesaid one end of said metallic separable connector to apply a substantialpressure to the first said metallic connector.

i 0 I i l

1. A combination which comprises: an enclosed fuseholder which has amale body portion, a female body portion, and means to releasablyinterconnect said body portions, said male body portion being hollow buthaving the outer end thereof closed, said female body portion beinghollow but having the outer end thereof closed, said male body portionand said female body portion and said means coacting to releasablyenclose and confine a cartridge type electric fuse, a metallic connectorcarried by and projecting outwardly from one end of one of said bodyportions, a metallic terminal carried by and communicating with theexterior of the other of said body portions, a water-tight seal betweensaid one body portion and said metallic connector, a second water-tightseal between said other body portion and said metallic terminal, saidmeans releasably holding the inner ends of said body portions inintimate engagement with each other to provide a water-resistant sealbetween said body portions, whereby said cartridge type electric fuse isnormally held within a water-resistant but readily openable enclosedfuseholder, a metallic separable connector which is located exteriorlyof said enclosed fuseholder and which normally has one end thereof intelescoped engagement with a portion of the first said metallicconnector and which has the other end thereof connectable to aconductor, and a body of insulating material which is mounted on anddirectly engages a portion of said metallic separable connector andwhich moves with said metallic separable connector whenever saidmetallic separable connector is separated from the first said metallicconnector, the first said metallic connector and said metallic separableconnector being dimensioned to provide a frictional securementtherebetween which is strong enough to normally maintain a lowresistance electrical connection between said fuse-holder and saidmetallic separable connector, the first said metallic connector and saidmetallic separable connector being dimensioned so said frictionalsecurement will automatically yield to permit the first said metallicconnector and said metallic separable connector to separate from eachother in response to a separating force which is smaller than theelastic limit of said fuseholder, said metallic separable connector andsaid portion of said first metallic connector, which is in telescopedengagement with said metallic separable connector, being located whollyexternally of said one body portion of said enclosed fuseholder, wherebysaid metallic separable connector can be pulled away from said firstmetallic connector while said means holds said male body portion andsaid female body portion in assembled relation and while the stressapplied to said enclosed fuseholder is well below the elastic limit ofsaid enclosed fuse-holder, whereby said enclosed fuseholder is protectedagainst damage from tensile forces which are applied to it by conductorsof the circuit that is protected by the cartridge type electric fusewithin said enclosed fuseholder.
 2. A combination as claimed in claim 1wherein the first said metallic connector is a male connector andwherein said metallic separable connector is a female conNector, andwherein said metallic separable connector is a sleeve that is slit atone end thereof to define fingers which can telescope over and tightlygrip said first said metallic connector, said metallic separableconnector having the other end thereof dimensioned to telescope over thebared end of said conductor.
 3. A combination which comprises: anenclosed fuseholder which has a male body portion, a female bodyportion, and means to releasably interconnect said body portions, saidmale body portion being hollow but having the outer end thereof closed,said female body being hollow but having the outer end thereof closed,said male body portion and said female body portion and said meanscoacting to releasably enclose and confine a cartridge type electricfuse, a metallic connector carried by and projecting outwardly from oneend of one of said body portions, a metallic separable connector whichis located exteriorly of said enclosed fuseholder and which normally hasone end thereof in telescoped engagement with a portion of the firstsaid metallic connector and which has the other end thereof connectableto a conductor, a body of insulating material which is mounted on anddirectly engages a portion of said metallic separable connector andwhich moves with said metallic separable connector whenever saidmetallic separable connector is separated from the first said metallicconnector, the first said metallic connector and said metallic separableconnector being dimensioned to provide a frictional securementtherebetween which is strong enough to normally maintain a lowresistance electrical connection between said fuse-holder and saidmetallic separable connector, the first said metallic connector and saidmetallic separable connector being dimensioned so said frictionalsecurement will automatically yield to permit the first said metallicconnector and said metallic separable connector to separate from eachother in response to a separating force which is smaller than theelastic limit of said fuseholder, said metallic separable connector andsaid portion of said first metallic connector, which is in telescopedengagement with said metallic separable connector, being located whollyexternally of said one body portion of said enclosed fuseholder, wherebysaid fuseholder is protected against damage from tensile forces whichare applied to it by conductors of the circuit that is protected by thefuse within said fuseholder, said metallic separable connector being asleeve with a plurality of fingers at said one end thereof.
 4. Acombination which comprises: an enclosed fuseholder which has a malebody portion, a female body portion, and means to releasablyinterconnect said body portions, said male body portion being hollow buthaving the outer end thereof closed, said female body portion beinghollow but having the outer end thereof closed, said male body portionand said female body portion and said means coacting to releasablyenclose and confine a cartridge type electric fuse, a metallic connectorcarried by and projecting outwardly from one end of one of said bodyportions, a metallic separable connector which is located exteriorly ofsaid enclosed fuseholder and which normally has one end thereof intelescoped engagement with a portion of the first said metallicconnector and which has the other end thereof connectable to aconductor, a body of insulating material which is mounted on anddirectly engages a portion of said metallic separable connector andwhich moves with said metallic separable connector whenever saidmetallic separable connector is separated from the first said metallicconnector, the first said metallic connector and said metallic separableconnector being dimensioned to provide a frictional securementtherebetween which is strong enough to normally maintain a lowresistance electrical connection between said fuse-holder and saidmetallic separable conneCtor, the first said metallic connector and saidmetallic separable connector being dimensioned so said frictionalsecurement will automatically yield to permit the first said metallicconnector and said metallic separable connector to separate from eachother in response to a separating force which is smaller than theelastic limit of said fuseholder, said metallic separable connector andsaid portion of said first metallic connector, which is in telescopedengagement with said metallic separable connector, being located whollyexternally of said one body portion of said enclosed fuseholder, wherebysaid fuseholder is protected against damage from tensile forces whichare applied to it by conductors of the circuit that is protected by thefuse within said fuseholder, said metallic separable connector being asleeve with a plurality of fingers at said one end thereof, and a splitring encircling said one end of said metallic separable connector toenable said one end of said metallic separable connector to apply asubstantial pressure to the first said metallic connector.